Limb shaker

ABSTRACT

A tree limb is vibrated to shake the fruit therefrom. A small lightweight internal combustion engine, such as is used for power saws, is used and it is isolated from the boom by a spring and the boom is isolated from the tree engaging finger by a second spring, thereby permitting the boom and limb to have a greater amplitude of movement than the reciprocating exciter of the engine assembly and also the limb engaging finger can move with respect to the boom to accommodate for different angles. The speed of the engine is adjusted to the natural frequency of the limb at which point the limb will have a large amplitude of vibration.

[ 51 Mar. 21, 1972 54 LIMB SHAKER Spencer B. Sitter, P.O. Box 415,McLean, Tex. 79057 22 Filed: June 23,1970

211 Appl.No.: 49,077

[72] lnventor:

[52] US. Cl ..56/328 TS [51] Int. Cl ..A0lg 19/00 [58] Field ofSearch..56/328, 328 TS,329

[56] References Cited UNITED STATES PATENTS 1,623,497 4/1927 Rurup..56/328 TS 2,542,665 2/1951 Gustafson.... 3,101,583 8/1963Ferguson..... 3.132458 5/1964 Russell et al. 3,174,269 3/1965 Londo..56/328 TS 3,212,250 10/1965 Aulabaugh et al. ..56/328 TS 3,457,7137/1969 Plummer ..56/328 TS 3,479,806 11/1969 Pool et al. .56/328 TSPrimary Examiner-Russell R. Kinsey AltorneyCharles W; Coffee [57]ABSTRACT A tree limb is vibrated to shake the fruit therefrom. A smalllightweight internal combustion engine, such as is used for power saws,is used and it is isolated from the boom by a spring and the boom isisolated from the tree engaging finger by a second spring, therebypermitting the boom and limb to have a greater amplitude of movementthan the reciprocating exciter of the engine assembly and also the limbengaging finger can move with respect to the boom to accommodate fordifferent angles. The speed of the engine is adjusted to the naturalfrequency of the limb at which point the limb will have a largeamplitude of vibration.

6 Claims, 4 Drawing Figures PATENTEDMRZ] I972 3,650,099

SHEET 1 OF 2 ENGINE mu: HTOEJ SPEHCE'K B. EDIT TEE- PATENTEUMARZIIQYESHEET 2 OF 2 IHVEHTOIQ SPENCER. E). slvTiia LIMB SHAKER CROSS-REFERENCETO RELATED APPLICATIONS On June 23, 1970, l filed application Ser. No.49,078 for Apron for Fruit Harvesting, which, together with the LimbShaker disclosed herein, works together as a unit forharvesting thefruit.

BACKGROUND OF THE INVENTION l. Field of the Invention This inventionrelates to harvesting fruit by shaking the tree. As used in this paper,fruit means the edible product of trees. Specifically included in thefruit to be gathered are pecans,

walnuts, plums, prunes, citrus fruits, peaches, apples, pears,

cherries, olives, etc.

2. Description ofthe Prior Art It is well known in the harvesting offruit that a tree can be shaken, thereby removing the fruit from thetree. For example, Gould et al., US. Pat. No. 3,120,091, discloses atractormounted boom which engages the tree and shakes it to shake thefruit from it.

Londo, US. Pat. No. 3,174,269, discloses a small vibrator for shakingonly one limb of a tree, utilizing an internal combustion engine as isused for power saws. Other examples of the prior art are shown in Poolet al.,-U.S. Pat. No. 3,479,806; Plumber, US. Pat. No. 3,457,713, andMays et al., US. Pat. No. 3,138,912.

SUMMARY OF THEINVENTION New and Different Function 1 have invented atree shaker which utilizes :the natural period of vibration of the treelimb,thereby enabling the effective shaking to be done with much lesspower; therefore, with a much smaller and lighter engine. Specifically,a variable speed engine is used so that the finger of the shaker engagesthe limb and then is excited with vibrations until the limb begins tovibrate vigorously, which will indicatethe natural frequency. The limbwill shake much more excessively than the exciter of theengine. This ispossible because ofa resilient linkage between the exciter and the boom,also, there is a second smaller resilient link between the boom andthe'limb engaging finger. The vibration of the boom is axial.

Objects of thislnvention An object of this invention is to harvest fruitfromitrees.

Another object is to harvest fruit by shaking the individual limbs witha small, lightweight engine wherein the limb vibrates with a greateramplitude than the engine exciter.

Other objects are to achieve the above without damage or injury to thetree.

Further objects are to achievethe above with a device that is sturdy,compact, durable, lightweight, simple, safe, efficient, versatile, andreliable, yet inexpensive and easy to manufacture, operate, andmaintain.

Still further objects are to achieve the above with a method that isversatile, rapid, efficient, and inexpensive, and does not requireskilled eople to adjust. operate; and maintain.

The specific nature of the invention, as well as other objects, uses,and advantages thereof, will clearly appear from the followingdescription and from the accompanying drawing, the different views ofwhich are not necessarily to the same scale.

BRIEF DESCRIPTION OF THE DRAWING:

FIG. 1 is a perspective view of an embodiment of this invention in useby a man with a fruit catcher or apron.

FIG. 2 is an enlarged elevational view of the shaker with portionsbroken away and shown in section.

FIG. 3 is an enlarged sectional view taken along line 3-3 of FIG. 2.

FIG. 4 is a schematic representation of the invention.

CATALOG OF ELEMENTS l0 Shaker l2 limb I4 tree 16 catcher I8 engine 20exciter 22 boom 24 slot 26 spring 28 end 30 stud 32 boom end 34 slot 36stub 38 stud 40 screws 42 space 44 sleeve 46 flange 48 body 50 wristspring 52 finger 54 tubing 56 tire 58 wires DESCRIPTION OF THE PREFERREDEMBODIMENT Shaker 10 is designed to be held in the hands of the operatorand toshake limb,l2 of tree 14 to cause the fruit to fall into catcher16. Although any type catcher could be used, the catcher which isdisclosed in application Ser. No. 49,078 is preferred. Shaking the fruitfrom the limb onto the ground and picking it up by hand is an operableprocedure.

The shaker 10 uses internal combustion engine 18 for the power.According to the developed technology of the present time, the onlycommercial source of power which is sufficiently lightweight to becomfortably carried in the hands of the operator is a gasoline poweredinternal combustion engine as is commonly used for power saws. However,it is entirely according to my invention that other sources of powercould be used such as electrical motors or fluid motors, eitherhydraulic or air pressure, or even stored animal power such as v a woundspring. According to the present state of technology to have themobility desired for this harvester, an electrical generator to supplyelectrical energy for an electrical motor would be undesirable or an aircompressor or hydraulic pump to supply the energy to a fluid motor isnot desirable; likewise, with the wound spring is not desirable.

The engine 18 is connected to exciter 20. Thus it may be seen thatengine 18 is a power means connected to the exciter 20 for vibrating theexciter and this vibration is in a direction aligned with thelongitudinal axis of elongated boom 22. The details of the connectionbetween the engine 18 and the exciter 20 have not been shown in thedrawings because such a transmission and vibrating mechanism is wellwithin the skill of those trained in the art. For example, Londo, supra,shows one means of achieving this. My preference is to purchase engineassemblies for power saws having reciprocating blades. Such units arecommercially available on the market, vibrating the exciter 1 7/16 inchstroke.

The frequency of the period orthe speed of the exciter 20 vibration mustbe adjustable. This is another reason I prefer to use an internalcombustion engine for power means 18 becausethey are readily adaptableby throttle setting to have adjustable speed output.

The exciter 20 is a cylindrical shaft which has slot 24 therein. Helicalspring 26, which is a resilient member, has flat exciter end 28 insertedinto the slot 24 and held securely in place by stud 30. The other end ofthe spring 26 is called boom end 32 and is inserted within slot 34 ofstub 36 and held securely in place by stub stud 38. It may be seen thatstub stud 38 is shaped so that the stub 36, including the stud, has acylindrical outline. The stub 36 is telescoped within the boom 22 andheld in place by screws 40. The spring 26 transmits both compression andtension. The majority of the length of the spring 26 is telescopedwithin or covered by boom 22. There is space 42 between the end of theboom 22 and the exciter 20. Therefore, the boom can have a greateramplitude of vibration than the amplitude of the exciter 20. The boom 22is telescoped within sleeve 44 which is rigidly attached by flange 46 tobody 48 of the engine unit 18. It will be obvious to those skilled inthe mechanical arts that they may insert a bushing 45 of suitablematerial between the sleeve 44 and the boom 22 to reduce friction, asmay be seen in the drawing. Thus the boom 22 is mounted for rectilinearreciprocation aligned with its axis.

One end of wrist spring 50 is attached to boom 22 by any convenientmeans and the other end of the wrist spring 50 is attached to V-shapedfinger 52 by any convenient means. The axis" or median of the V-shapedfinger is normal to the axis of the boom 22 and the V-shaped finger 52lies in the same plane as the boom 22. The spring 50 is connected to the\'-shaped finger about midway of one ofthe legs of the V. The drawing isspecifically referred to for the particular arrangement of parts in thisarea. The V-shaped finger 52 is made of tubular metal and is covered bya resilient covering. I have found that it is desirable to cover therubber tubing 54 with a tough, resilient material, which is alsoflexible. I have found that bicycle tires 56 are ideally suited forthis. They can be slipped over and held in place by wires 58 through thesidewall so that the beads are pulled together with the wires. Bicycletires are suitable for this because they are readily available in allparts of the world and they are tough and resilient and still flexible.

One of the specific purposes for which the shaker is designed is for theharvesting of olives, and olive trees are valuable. It is important notto harm an olive tree as by scarring the branches. When the limb isvibrated, there is violent movement of fingers 52 in contact with thelimb 12. Therefore, It is desirable that the fingers 52 not beat thelimb or otherwise harm it. Also, in this connection, the main purposefor wrist spring 50, although it is a resilient connection between theboom 22 and the finger 52, is not for the vibratory effect, but for thefitting effect. I.e., the fingers can make a snug, secure contact withthe limb 12, even though the boom may not be in good position withrespect to the limb. More often than not, probably, the boom 22 will notbe at right angles to the limb 12, however, because of the wrist spring50, which is a helical spring, the finger 52 can twist and move so thatit is at right angles to the limb and will fit securely thereon.

OPERATION Normally the engine unit with the internal combustion engine18 will have a speed responsive clutch; therefore, the operator of thelimb shaker 10 can start the engine and have it running at slow speedwithout the exciter vibrating. The person holding the shaker in hishands can then raise the finger 52, placing it over the limb 12 to beshaken to harvest the fruit therefrom. With it in place, the operatorincreases the speed of the engine 18 until the clutch engages which willcause the exciter 20 to reciprocate. The reciprocation or vibrationof,the exciter 20 will be transmitted through the resilient member whichis the spring 26 to the boom 22. Normally, the boom is connected withonly medium resilience to the limb 12. Normally the boom and the limbwill vibrate with approximately the same amplitude and, generally, theamplitude of vibration of the limb and the boom will be less than theamplitude of the vibration of the exciter 20. The operator increases thespeed of the engine 18 by advancing the throttle or by whatever speedcontrol means are provided. When the speed of the engine vibrates theexciter 20 at a frequency which matches the natural frequency ofvibration of the tree limb 12, the limb will vibrate violently. At aboutthe natural frequency of the tree limb 12, the amplitude of vibration ofthe limb and the boom 22 will be greater than the amplitude of vibrationof the exciter 20. Le, the exciter 20 does not vibrate or shake the limbby excessive force, but it excites vibration into the limb at thenatural frequency of the limb; therefore, it is the resilience of thelimb 12 which causes it to vibrate all by itself with the exitation fromthe exciter 20. For this reason, a very small amount of power isrequired to shake the limb; therefore, an extremely lightweight engine18 is usable.

When the natural frequency of the limb 12 is reached, the limb willshake violently and all fruit on it will shake free of the limb and falldownward, responsive to earths gravity. Thereafter, the throttle and thespeed of the vibration can be reduced until the clutch disengages andthe exciter 20 no longer vibrates and the fingers 52 removed from thelimb and then moved to the next limb where it is engaged and vibrated atits natural frequency to deliver the fruit from it.

Those familiar with vibrations will recognize that it is difficult topredict exactly how vibrations will work and the effect of resiliencyand damping the resiliency in the various parts of the vibratory system.In the embodiment described, through experimentation it is founddesirable that sometimes spring 26 not be entirely free from dampingaction. Specifically, I have found in certain instances with certaintrees, it is desirable to fit a rubber plug within the spring 26. Le,the external diameter of the cylindrical rubber plug is slightly largerthan the inside diameter of the spring 26. Therefore, with the rubberplug fitted into it, there is certain friction and change in theresilience between the spring 26; therefore, certain changes in theresiliency and damping action with which the vibration is transmittedfrom the exciter 20 to the boom 22. Although it seems that in certaincases it increases the vibration upon the limb; however, it may be thatthis merely broadens the frequency range of which sympathetic vibrationsare obtained. It is believed that if there is no damping in the naturalwood of the tree limb 12, there is a very narrow range of frequency ofwhich there is a natural vibratory response and the speed of the engine18 must be very precisely matched to this natural frequency ofvibration. However, if more damping is introduced, the frequency rangeof natural vibration is increased so that the speed of the engine is notso critical.

The embodiment shown and described above is only exemplary. I do notclaim to have invented all the parts, elements or steps described.Various modifications can be made in the construction, material,arrangement, and operation, and still be within the scope of myinvention. The limits of the invention and bounds of the patentprotection are measured by and defined in the following claims. Therestrictive description and drawing of the specific example above do notpoint out what an infringement of this patent would be, but are toenable the reader to make and use the invention.

SUBJECT MATTER CLAIMED FOR PROTECTION I claim as my invention: 1. In alimb shaker having a. a finger for engaging a limb ofa tree, b. anelongated boom connected to the finger, c. an exciter connected to theboom, and (1. power means connected to the exciter for vibrating theexciter in a direction aligned with the longitudinal axis of the boom;e. the improvement comprising: f. a resilient member interconnecting theexciter to the boom. 2. The invention as defined in claim 1 with theadditional limitation of g. a resilient member interconnecting the boomto the finger. 3. The invention as defined in claim 1 with theadditional limitation of g. means connected to the power means forchanging the frequency of vibration of the exciter. 4. The invention asdefined in claim 3 with the additional limitation of e. the improvementcomprising: f. a resilient member interconnecting the boom to thefinger. 6. The invention as defined in claim 5 with the additionallimitation of g. means connected to the power means for changing thefrequency of vibration of the exciter.

1. In a limb shaker having a. a finger for engaging a limb of a tree, b.an elongated boom connected to the finger, c. an exciter connected tothe boom, and d. power means connected to the exciter for vibrating theexciter in a direction aligned with the longitudinal axis of the boom;e. The improvement comprising: f. a resilient member interconnecting theexciter to the boom.
 2. The invention as defined in claim 1 with theadditional limitation of g. a resilient member interconnecting the boomto the finger.
 3. The invention as defined in claim 1 with theadditional limitation of g. means connected to the power means forchanging the frequency of vibration of the exciter.
 4. The invention asdefined in claim 3 with the additional limitation of h. a resilientmember interconnecting the boom to the finger.
 5. In a limb shakerhaving a. a finger for engaging a limb of a tree, b. an elongated boomconnected to the finger, c. an exciter connected to the boom, and d.power means connected to the exciter for vibrating the exciter in adirection aligned with the longitudinal axis of the boom; e. theimprovement comprising: f. a resilient member interconnecting the boomto the finger.
 6. The invention as defined in claim 5 with theadditional limitation of g. means connected to the power means forchanging the frequency of vibration of the exciter.